The present invention generally pertains to apparatus which read magnetically-encoded data from or write such data onto a moving magnetic medium, and more particularly it pertains to a device for maintaining contact between magnetic medium on a moving card and a magnetic transducer surface.
As in known in the art, transport systems are available for processing flexible magnetically-encoded tickets for purposes such as transit fare transactions. Such an apparatus is taught, for example, in U.S. Pat. No. 4,377,828 to Hayman et al. The ticket transport of the Hayman patent includes a channel which is adapted to have a ticket propelled through it. A transducer is positioned adjacent the channel for reading data from or writing data onto a magnetic strip on the ticket. A roller is provided in the ticket channel opposite the transducer, which operates to press the ticket against the transducer as it moves through the channel. The pressure is for the purpose of bringing the magnetic strip and the transducer into a close and precise contacting relationship. Such a relationship is characterized by an unvarying spatial orientation of the magnetic strip on a card and the magnetic transducer, which must be maintained while the card is propelled through the channel.
Prior art mechanisms for positioning an encoded recording medium, such as magnetic tape or punched cards against a read or write head are well-known. Such mechanisms include one which moves from a rest position into an operating position for either tensioning the medium against or pressing it into contact with a transducer. Similar tensioning mechanisms are disclosed in U.S. Pat. Nos.: 3,217,996; 3,257,057; 3,370,157; 3,641,283; 3,984,049; and 4,129,892. However, the use of such positionable tensioning or contacting mechanisms in a high-speed ticket transport mechanism such as is described above is impractical. A positionable tensioning device in such an application would have to be provided with an asynchronously operating, high-speed position actuater which could respond to the sporadic introduction of tickets into the transport and the high speed with which they are propelled therethrough. As is known, a positionable tensioning device and its associated actuating circuitry can increase the cost and reduce the reliability of a transport apparatus in which they are employed.
In U.S. Pat. No. 3,109,924, an apparatus is described for maintaining a moving, information-bearing card in close relationship with a card reader by providing a rotating drum having a high-friction surface which engages an endless belt. The card is nipped between the belt and the rotating high friction surface, and moved thereby past the transducer. This card reader is also unsuitable for use in a high-speed ticket transport for the reason that the high-friction portion of the drum can wear and slough material onto the processed card, thereby obscuring information on the card. Furthermore, the endless belt will stretch and require periodic replacement.
Another mechanism for maintaining a magnetic card in close relationship with an associated read/record head is disclosed in U.S. Pat. No. 3,893,173 to Taggart et al. In the Taggart apparatus, the magnetic card is conformed to the contour of the magnetic head through the action of a plurality of spring-loaded balls which press the card against the magnetic head. The engagement balls are displaced against the spring and the card is slid between them and the surface of a card guide. Thus, the balls are deflected upward by the edge of the card and require a minimum displacement force which is related to the physical characteristics of the card. Manifestly, the physical requirements will limit the composition and the thickness of the card and bar the use of certain materials and dimensions.
Therefore, it is the principal object of the present invention to provide a mechanism for maintaining physical contact between the magnetic medium of a moving farecard and a magnetic transducer, which eliminates the need for a positionable engagement mechanism, reduces the requirement for periodic maintenance, and which will not obscure the magnetic information on the card or limit the card's composition or dimension.
This and other objects of the invention will become readily apparent in the ensuing specification when taken together with the drawings.